I started a new game, and prompted by the achievement icon of a radio carried that thing around with me in the first level. As I proceeded to the first big button, the radio went all static then started recieving morse code (!) and a light on it went from red to green.
Quit out, did some quick searching and found a few articles. This from The Escapist summed it up best as of this posting:
Anyone here play portal that knows morse code?Well, It looks like ValVe may finally be teasing portal 2. The latest update apparently adds hidden radios to every chamber of Portal, radios which appear to be sending some kind of message, possibly in Morse code.
New Achievement
A mysterious announcement
Alright Fanboys, we got a mysterious message that needs deciphering, so hop to it!
*UPDATE* The zealots over at the steam forums have already translated the first message from Morse code. it reads:
"interior transmission active
external data line active
message digest active"
It reads an awful lot like a system booting. Looks like something might still be alive...![]()

Certainly has me intrigued